Human sessions only

Only humans set the apply policy for agent branch sessions and approve branch merges (D20: the human decides when agent work lands).

#Common causes

• An agent session called collab.policy or branch.merge.

#Fixes

• Submit the branch with branch.submit; a human merges it, or the apply policy does.

• Code: ARA2511

• Constant: collab::HUMAN_ONLY

• Reported by: ara-collab